Composition of matter for blackboards, &amp;c.



106. COMPOSITIONS, Cross Refe COATING R PLASTIC. rencel EXAMINER UNITED STATES PATENT OFFICE.

LUCIUS OBRIEN, OF OROOKSTON, MINNESOTA.

COMPOSITION OF MATTER FOR BLACKBOARDS, 84.0.

SPECIFICATION forming part of Letters Patent N 0. 657,001, dated August 28, 1900.

Applicationfiled April 5,1900. Serislllo.ll,'783. (N0 specimens.) 2 h; i g r To (l-ZZ whom/it may concern.- when completed will be about twenty-four Ile it known that I, LUCIUS OBRIEN, a citi- (24) pailfuls, which will make about one hunzen of the United States, residing at Crooksdred and twenty-five (125) square yards of 0 ton, in the county of Polk and State of Minblackboard. I use putty-lime in preference 5 ncsota, havcinvented certain new and useful to any other kind of lime or substance be- Improvements in Compositions of Matter; cause it takes the place of alcohol in cutand I do declare the following to be a full, ting the lampblack and is much superior clear, and exact description of the invention, thereto and makes a much more durable such as will enable others skilled in the art to board, one which will not absorb chalk or [O whichitappertains to make and usethe same. other foreign matter and rot or chip oif, as

My invention relates to a composition of in boards made up with alcohol or a similar matter used in producing on the wall of a substance or ordinary lime. The gipeganis school building or other building where deused for the purpose of making the board six-able blackboards for the use of pupils and s on n d, spripgy, so that by being some- |5 othersin demonstratingsolutions of examples what yielding it is much easier to work on. in mathematics, delineating maps, and the Having thus fully described my invention, like in chalk; and the invention consists in what I claim, and desire to secure by Letters a com position of putty-lime, sand, lampblack, Patent, isvinegar, Portland cement, plaster-of-paris, 1. Acomposition of matter designed for use 20 and water in the manner and in the proporin the production ofblackboards and like surtions as hereinafter set forth. faces, the same consisting, essentially, of

In compounding the composition of matter putt dime, sangl lampblack, vinegagPortfor blackboardsl employ the following-named laii Geiii'ent, plaster-of-paris, and water, comingredients in substantially the proportions bined substantially in the manner and pro- 2 5 hereinafter set forth: I use twelve (12) pailportions specified.

fuls of utt dime-that is, slaked lime made 2. A blackboard composition which conin water 111 about the consistency of putty or tains vinegar as an essential ingredient to common plaster ready for application to a render the composition spongy and springy, wall-nine (9) pailfuls of clean shar sand substantially as described.

0 twenty-six (26) pounds of lam black one In testimony whereof I have hereunto set quart of vine ar one (1) par u o ortland my hand in presence of two subscribing witcement and onel l lpailfulof laster-ofaris. nesses.

"The pail referred to is a common wooden pail holding about ten (10) or eleven (11) quarts.

35 In mixing these ingredients and bringing Witnesses:

them to proper consistency about two (2) LOUIS E. GOSSMAN, pailfuls of water are used, and the mixture EDMUND M. \VALSH.

LUCIUS- OBRIEN. 

